Technologies of improving a reception state of radio waves to be transmitted are widely used.
For example, in a portable phone and the like equipped with a global positioning system (GPS) and the like, a device on a reception side detects a reception state of radio waves transmitted from a base station which is a transmission side device, and when it enters a state in which the radio wave cannot be received or reception sensitivity is deteriorated, reception difficult position information is stored on the basis of the GPS. Then, when the reception state improves, the reception side device transmits the reception difficult position information to the base station. There is suggested the technology of improving the reception status of the portable phone by a method in which the base station receives the reception difficult position information from a plurality of portable phones, thereby specifying an area where it is difficult to receive the radio wave, and the base station is increased, for example, in order to improve the reception status of the specified area by such a configuration (refer to Patent Document 1.